بررسي استانداردهاي سفالومتريك دانش آموزان دختر داراي الكوژن نرمال در همدان در سال تحصيلي 79-1378

The important base of orthodontic treatment is correct diagnosis . One of diagnostic tools is comparing craniofacial skeleton in lateral cephalogram of patient with the normal ones . There are differences in normal standards between different races .The present study was carried out with the aim of determining and assessing the cephalometric standards of girls with the age of 17 to 20 years old in Hamadan . Among 1305 girls of Preuniversity centers , 25 persons were selected based on index of IOTN and normal occlusal standards . Lateral cephalograms were obtained in Natural Head Position . 22 cephalometric variables ( 15 angles , 5 lines , 2 ratios ) were determined & measured three times by an orthodontist . T student test was used for analysis . The length of anterior cranial base in our study (72.57±3.75) was significantly less than Michigan standards ( 76.9 ± 3.9 , p50.0056) .There is a significant tendency to more straight profile in this evaluation (Npog - TH = 88.33 ± 4.65) in comparing with Cooke ʹs study( 80.8 ± 3.1 , p<-0.001) .Also there was significantly less protrusion of mandibular incisors in our study( L1-TH=120.05 ± 7.6) versus Cookeʹs standards(127.8 ± 6.3). Mandibular plan angle in present study ( GoGn - TH = 23.18 ± 5.55) had significantly more counter clockwise rotation versus Viazis repports ( 27.5 ± 7 , p< 0.001) . It is important to consider the ethnic and racial variations in our ideal treatment plan . Majority of standards achieved from europian whites therefore it seems there is necessary to design a broader investigation for assessing the cephalometric standards in our country .